1. Field of the Invention
This invention relates to a sound insulating layer for a vehicle, and more particularly to a sound barrier mat having an integrally formed steering column boot.
2. Description of the Related Art
In most contemporary automobiles, a steel fire wall separates the engine compartment from the passenger compartment. To reduce the transmission of sound from the engine compartment through the fire wall and into the passenger compartment, a sound barrier mat (otherwise known as a dash mat) is typically molded of an elastomeric material. The dash mat is mounted to and substantially overlies the fire wall such that an outer surface of the mat is in contact with a bottom surface of the vehicle carpet and extends beyond the carpet to an upper portion of the fire wall behind the instrument panel. An absorber layer, typically constructed of an open cell foam material, can be attached to the dash mat to interface between the sound barrier mat and the fire wall.
During installation of the dash mat, an opening for the vehicle steering column in the dash mat is aligned with a corresponding opening in the fire wall. Other formations in the dash mat are also aligned with various other features on or protruding from the fire wall. The dash mat is then secured to the fire wall on the passenger compartment side. A steering column is subsequently inserted through the aligned openings in the fire wall and dash mat. A flexible boot is installed snugly around the steering column and then attached to the fire wall or dash mat with fasteners. Installation of the boot and dash mat in this manner requires a plurality of different parts and fasteners. The plurality of parts and fasteners results in increased inventory, expense, and installation time. Moreover, the seam between the boot and dash mat or fire wall is subject to leakage. Noise, air, water, etc. may undesirably transfer from the engine compartment to the passenger compartment through the seam.